Twisted conductors and cables and method and apparatus for making the same



J. 1 TWISTED CONDUCTOR-S AND CABLES AND METHOD APPARATUS FOR MAKING THE SAME Filed larch 12, 1957 Jan. 20, 1959 i c. LILLY 2,859,316

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Unite grates Patent TWISTED CONDUCTORS AND CABLES AND METHOD AND APPARATUS FOR MAKING THE SAME Joseph C. Lilly, Plainfield, Conn., assignor to The Plastic Wire & Cable Corporation, Jewett City, Conn, a corporation of Connecticut Application March 12, 1957, Serial N 0. 645,599

14 Claims. (CI. 57-93) This invention relates to electrical wires or conductors and cables made therefrom and to the method and apparatus for making the same.

More particularly, the present invention relates to an improved twisted pair circuit for use as an open wire or assembled into cables for the transmission of intelligible electric signals.

Heretofore, in producing cables, it has been the practice to produce twisted pairs which are distinct by reason of the fact that each has twists of predetermined fixed length. In use in cables, neighboring or juxtaposed pairs or subassemblies have different predetermined twist lengths so as to cause the members of one pair to be transposed with respect to those of another pair in order to reduce to a minimum inductive disturbances as, for example, cross-talk when the cable is used for telephone purposes. This, therefore, required a predetermined number of different and distinguishable subassemblies, each having a dilferent rate of twist or twist length and that each pair be identified. It also required that the pairs be located in predetermined relation in the cable and their position maintained in the cable. This required the manufacture and storage of a number of different subassemblies and particular care in the selection and assembly of them into a cable, all of which adds to the cost of the cable.

The present invention overcomes these difficulties and disadvantages of the prior constructions by providing a single twisted pair having the lengths of the twists in the pair continuously varying throughout and preferably controlling the variation at random so that there is no fixed pattern in the twist variation whereby lengths of the one twisted pair can be placed adjacent one another in open circuits or in cables with a minimum of difficulty from inductivedisturbances therebetween.

In producing the novel twisted pair, the present invention embodies a novel apparatus and method for making the twisted pair. In the novel apparatus the relative rate of speed between the twisting device and the capstan is constantly varied and the means for varying said relation is constantly altered at random so as to produce an infinite variation in the length of the twists in the twisted pair.

A feature of the present invention resides in the fact that but a single twisted pair need be produced which can be safely utilized in an open circuit or in a cable without the danger of electric disturbances being present between the twisted pairs therein, thus eliminating the necessity of making and storing a large number of different and distinguishable pairs or subassemblies.

Another feature of the invention resides in the fact that with the present invention the cable assembly and construction can be simplified.

Other features and advantages of the invention will be apparent from the specification and claims when considered in connection with the drawings in which:

Figure 1 shows a diagrammatic view of theapparatus.

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Fig. 2 shows two twisted pairs in side-by-side relation as they would appear in a cable.

Fig. 3 shows a speed time chart showing the variation of capstan speed.

Fig. 4 shows one form of speed-changing device.

As shown in the drawings, a pair of wires a and b, preferably insulated electrical conductors, are fed from reels 10, 11 through a conventional twisting device 12 which includes a rotatable flyer 13 driven from a motor 14 or other source of power so as to carry the wire a around the wire b as it passes through the guide 15 and form a twist therewith as the wires are drawn therethrough by a capstan 16. The twisted pairs are then fed to a takeup spool 17 which may be driven by a usual constant torque motor 18 or the like means. It will be apparent that the length of each twist depends upon the rate at which the wire is drawn by the capstan through the twisting device, i. e., the rate of speed of the capstan with respect to the rate of rotation of the fiyer, so that by changing gears in the drive to the capstan a twisted pair having the twists of a predetermined length could be produced. The foregoing describes a standard machine now in use for forming twisted pairs having a uniform length of twist throughout.

In contradistinction to such a twisted pair, the present invention provides a novel twisted pair and method of making the same in which the length of successive twists therein is continuously changing. As shown in the top pair of the cable of Fig. 2, the length of the twist decreases to R, increases to S, decreases to T and then increases while in the lower pair the length of the twist increases to U, decreases to V, increases to X and decreases. It will be noted that the rate of change in length is constantly varying and the reversals thereof occur at random so that when two or more twisted pairs are put in juxtaposition in a cable the danger of crosstalk or the disturbances in the signal is substantially eliminated.

Since the length of twist in each pair is constantly varying, the present invention greatly simplifies the method and manufacture of novel cables because it is no longer necessary to maintain stocks of twisted pairs each having a predetermined different length of twist and it is no longer necessary to arrange the pairs having different length twists therein in predetermined position in the cable and to maintain them in said positional arrangement to prevent inductive disturbances in the cable.

While either the speed of the flyer or capstan can be varied, in the illustrated form of the invention the capstan, as shown in Fig. 1, is driven from the motor 14 through a speed-changing device 19.

Any suitable variable speed drive may be used. One such drive is shown in Fig. 4 wherein the input shaft 20 driven from motor 14 has an expansible pulley 21 thereon and the output shaft 22 has an 23 thereon. A belt 24 connects the pulleys. A pair of pivoted levers 25, 26 are connected to the sides of the pulleys to move the sides in opposite directions to increase the belt-engaging diameter of one pulley and decrease the belt-engaging diameter of the other pulley to vary the speed between the shafts 20 and 22. The levers have their ends pivotally connected to nuts 27 threaded on the oppositely threaded portion of a rotatable adjusting shaft 28. By controlling the rotation of shaft 28, it will be seen that the relative speed of the capstan and the fiyer can be regulated to control twist.

In order to provide for a constantly varying length of twist in the wires, the present invention controls the rotatable member or shaft 28 of the variable speed drive. While the shaft 28 can be driven from the motor 14 or by a separate variable speed motor having suitable controls the length of expansible pulley thereon, in the illustrated form of the invention the rotating member 28 is driven from the capstan 16 through a gear reducer 29 so as to rotate the screw within the speed changer or variable speed drive so as to cause the levers 25, 26 to be pivoted about their pivots and move the side of the pulleys toward or away from one another to increase or decrease the effective diameter of the pulleys and change the speed of the capstan. Since the control member 28 is driven with the capstan which is being rotated at a variable speed, the change in speed of the speed-changing device will also be variable so that the change of length of the twist in the pair is continuously varying.

In order to further modify the twist in the pair, the present invention provides a novel control means for controlling the rotating adjusting shaft of the speed changer. In the herein form of the invention a reversing mechanism 3t) is inserted in the drive for the shaft 28 and a control for the reversing mechanism is provided to periodically reverse the rotation of the shaft. this control can take the form of a tape, cam or any other type of programming device capable of effecting random operation of the shaft, it is herein illustrated as comprising a rotatable screw 31 having a nut 32 thereon and driven with the rotating shaft 28. The nut has a switch 33 thereon connected to the control box 34 housing the usual electrical relays and air control means (not shown) for controlling the usual fluid operated reversing clutch means (not shown) in the reversing mechanism so that by actuating the reversing switch the direction of rotation of the shaft 28 can be reversed.

The control of the switch can be carried out by any suitable programming device such as tape, cams, punch cards, photocells and the like devices capable of producing random reversal of the shaft 28. In the illustrated form of the invention, it comprises a drum 35 having projecting at random from its surface a plurality of actuators 36. The drum is positioned adjacent the screw and is rotated to cause the actuators to be moved into the path of movement of the reversing switch 33 to engage the same and operate the reversing means to cause a reversal of rotation of the shaft 28. The drum can be driven in timed relation with the shaft 28 or by motor 14 but it is herein illustrated as being driven by a separate motor 35a which can be a single speed or variable speed motor as desired. Preferably, the drum is provided with continuous end projections 37 which form limit controls for actuating the switch and reversing the changing speed at predetermined points to define the maximum and minimum length of twist in the pair.

With this construction it will be seen that the rotation of the shaft 28 is continually varied between limits and reversed at random to cause the variable speed drive to continuously vary at random the speed of the capstan with respect to the fiyer drive and hence the length of each twist in a twisted pair.

The speed-time chart shown in Fig. 3 is a section of a chart taken on an actual run of a machine of the present invention and graphically shows the variation in the speed of the capstan on a time basis, and, since the speed of the fiyer is constant, the chart shows the variation between the speed of the capstan and fiyer drives. The notations at the left in Fig. 3 indicate the speeds representing the maximum and minimum lengths of twist in the pair and the zigzag curve having irregular reversals clearly show the continuous and random nature of the change in relative speeds and resulting increasing and decreasing lengths of twist. The portions of the curve below the minimum length line wereproduced during the starting and stopping of the machine.

The control of the present invention can be added to existing machines without substantial alteration thereto or can be built into the machine as original equipment.

Although the present machine is intended to produce twisted pairs having constantly varying lengths of twist,

While it can be adjusted to produce twisted pairs of fixed constant length of twist. This is accomplished by adjusting the capstan speed to the required speed as shown on the tachometer 38 on the output shaft 22 and then locking the adjusting shaft 28 against further adjustment by a suitable clamp 39 actuated by a handwheel 40 on the control panel 41. Also, the clutch in the reversing mechanism can be rendered inoperative, by means of handwheels 42, 43 on the control panel so that the connection will cease to drive the shaft 28 whereupon the capstan will be riven at a constant rate of speed to produce twists of constant length.

It will be seen, therefore, that the machine of the present invention is very versatile in that it can produce twisted pairs having a fixed length of twist or a continuously varying length of twist as required.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. The method of forming a pair of twisted conductors having a random twist therein comprising the steps of twisting the wires by a twister operated at a uniform speed, drawing the wires through the twister at a continuous variable speed to cause the length of twists formed by the twister to be of varying lengths, and varying at random the direction and rate of variation of the speed of drawing said wires through the twister.

2. The method of forming a cable including a plurality of juxtaposed twisted pairs of twisted conductors comprising the steps of twisting the conductors of each pair to form twists therein, continuously and at random varying the lengths of said twists, and positioning a plurality of said twisted pairs of conductors in side-by-side relation, the continuous and random variation of the twists in adjacent pairs causing the conductors to be transposed and in non-inductive relation whereby inductive disturbances in the cable are prevented.

3. in a machine for forming twisted pairs of wire, twisting means for twisting a pair of wires together, drawing means for drawing said wires through the twisting means, means for continuously varying the relative speeds of the twisting means and drawing means, and means for varying at random the direction and rate of variation of said relative speeds to continuously vary at random the length of each twist in the twisted pair.

4. In a machine for forming twisted pairs of wire having twisting means for twisting a pair of wires together, means driving the twisting means at a fixed speed, a capstan for drawing the wires through the twisting means, and variable speed drive for driving the capstan, the improvement wherein there is provided a means for continuously varying the variable speed drive to vary the speed of the capstan with respect to the fixed speed of the twisting means whereby the wires are drawn through the twisting means with a variable speed to vary the length of each twist in said wires.

5. In a machine for forming twisted pairs of wire having twisting means for twisting a pair of wires, means driving the twisting means at a fixed speed, a capstan for drawing the wires through the twisting means, and a variable speed drive for driving the capstan, the improvement wherein there is provided a means for continuously varying the variable speed drive between fixed limits to vary the length of each twist in said wires between predetermined limits, and means operable at random between said fixed limits for reversing the direction of variation of said variable speed drive whereby said twisted wire has random length twists between said predetermined limits.

6. In a machine for forming twisted pairs of wire having twisting means for twisting apair of wires together, means driving the twisting means at a fixed speed, a capstan for drawing the wires through the twisting means, and a. variable speed drive for driving the capstan, the

a improvement wherein there is provided means driven with the capstan for continuously varying the variable speed drive to vary the speed of the capstan with respect to the fixed speed of the twisting means whereby the wires are drawn through the twisting means with a variable speed to vary the length of each twist in said wires.

7. In a machine for forming twisted pairs of wire having twisting means for twisting a pair of wires, means driving the twisting means at a fixed speed, a capstan for drawing the wires through the twisting means, and a variable speed drive for driving the capstan, the improvement wherein there is provided means for continuously varying the variable speed drive, and means for varying at random the direction and rate of variation of the variable speed drive whereby the wires are drawn through the twisting means at a random variable speed to vary the length of each twist in said wires.

8. In a machine for forming twisted pairs of wire having twisting means for twisting a pair of wires together, means driving the twisting means at a fixed speed, a cap stan for drawing the Wires through the twisting means, and a variable speed drive for driving the capstan, the improvement wherein there is provided means for continuously varying the variable speed drive and means for varying the last-named means at random to continuously increase and decrease the speed of the capstan with respect to the fixed speed of the twisting means whereby the wires are drawn through the twisting means with a variable speed to vary the length of each successive twist in said wires.

9. In a machine for forming twisted pairs of wire having twisting means for twisting a pair of wires together, means driving the twisting means at a fixed speed, a capstan for drawing the wires through the twisting means, and a variable speed drive for driving the capstan, the improvement wherein there is provided means comprising a rotatable member connected to the variable speed drive for continuously varying said drive and means for re versing the rotation of said shaft at random to continuously increase and decrease the speed of the capstan with respect to the fixed speed of the twisting means whereby the wires are drawn through the twisting means with a variable speed to vary the length of each successive twist in said wires.

10. In a machine for forming twisted pairs of wire having twisting means for twisting a pair of wires together, means driving the twisting means at a fixed speed, a capstan for drawing the wires through the twisting means, and a variable speed drive for driving the capstan, the improvement wherein there is provided means comprising a rotatable shaft connected to the variable speed drive to adjust the speed thereof, means for continuously rotating said shaft to vary the variable speed drive, and means for reversing the rotation of said shaft at random to continuously increase and decrease the speed of the capstan with respect to the fixed speed of the twisting means whereby the wires are drawn through the twisting means with increasing and decreasing speed to vary the length of each successive twist in said wires.

11. In a machine for forming twisted pairs of wire having twisting means for twisting a pair of wires together, means driving the twisting means at a fixed speed, a capstan for drawing the wires through the twisting means, and a variable speed drive for driving the capstan, the improvement wherein there is provided means comprising a rotatable shaft connected to the variable speed drive to adjust the speed thereof, means for continuously rotating said shaft to vary the variable speed drive, means including electrically controlled reversing means connected to said shaft, a screw driven with said rotating member, a nut movable on the screw and having a control switch thereon connected to the reversing means, and a plurality of movable actuators adapted to be positioned in the path of movement of said control switch to operate said switch at random to actuate the reversing mechanism for reversing the rotation of said shaft at random to continuously increase and decrease the speed of the capstan with respect to the fixed speed of the twisting means whereby the wires are drawn through the twisting means with increasing and decreasing speed to vary the length of each successive twist in said wires.

12. In a machine for forming twisted pairs of wire having twisting means for twisting a pair of wires together, means driving the twisting means at a fixed speed, a capstan for drawing the wires through the twisting means, and a variable speed drive for driving the capstan, the improvement wherein there is provided means comprising a rotatable shaft connected to the variable speed drive to adjust the speed thereof, means for continuously rotating said shaft to vary the variable speed drive, and means including electrically controlled reversing means connected to said shaft, a screw driven with said rotating member, a nut movable on the screw and having a control switch thereon connected to the re versing means, and a rotatable member adjacent the screw and having a plurality of actuators thereon, means rotating said member relatively to said screw to position said actuators in the path of movement of said control switch to operate said switch at random to actuate the reversing mechanism for reversing the rotation of said shaft at random to continuously increase and decrease the speed of the capstan with respect to the fixed speed of the twisting means whereby the wires are drawn through the twisting means with increasing and decreasing speed to vary the length of each successive twist in said Wires.

13. In a machine for forming twisted pairs of wire having twisting means for twisting a pair of wires together, means driving the twisting means at a fixed speed, a capstan for drawing the wires through the twisting means, and a variable speed drive for driving the capstan, the improvement wherein there is provided means comprising a rotatable shaft connected to the variable speed drive to adjust the speed thereof, means for continuously rotating said shaft to vary the variable speed drive, and means including electrically controlled reversing means connected to said shaft, a screw driven with said rotating member, a nut movable on the screw and having a control switch thereon connected to the reversing means, and a motor driven cam adjacent the screw and having a plurality of actuators thereon adapted to be positioned in the path of movement of said control switch to operate said switch at random to actuate the reversing mechanism for reversing the rotation of said shaft at random to continuously increase and decrease the speed of the capstan with respect to the fixed speed of the twisting means whereby the wires are drawn through the twisting means with increasing and decreasing speed to vary the length of each successive twist in said wires.

14. The method of forming a pair of twisted wires comprising the steps of twisting the wires by a twister, drawing the wires through said twister, continuously varying the speed ratio between the speed of twisting and the speed of drawing said wires to produce varying lengths of twist in said twisted pair, and varying at random the direction and rate of variation of said speed ratio.

References Eited in the file of this patent UNITED STATES PATENTS 491,109 Holman Feb. 7, 1893 497,335 Patterson May 16, 1893 502,262 Patterson July 25, 1893 1,784,859 Weston Dec. 16, 1930 1,946,941 Leonard Feb. 13, 1934 1,988,586 Deacon Jan. 22, 1935 2,089,193 Dreyfus Aug. 10, 1937 

